But does she travel through space?
In my mind, there is a competition between Jewel Staite and Sam Rockwell. Not sure if motion novels count though.
Based on memory and a brief glance at IMDb, here's what might be the count so far:
Jewel Staite - Catalina in Space Cases, Kaylee in Firefly/Serenity, Dr. Jennifer Keller and Ellia in Stargate: Atlantis (I assume these are different characters, as I haven't seen it). That's 4, unless I'm missing something (or unless one of her Stargate characters never left their home planet).
Sam Rockwell - Guy Fleegman in Galaxy Quest, Zaphod Beeblebrox in The Hitchhiker's Guide to the Galaxy, Sam Bell and [spoiler omitted] in Moon. So that's 4, unless I've missed or miscounted something.

TenTonParasol: Not just David Hewlett, from the looks of it. Pretty sure Tori Higginson (Dr. Elizabeth Weir) is the Don LaFontaine for the trailer (aka the narrator giving a plot synopsis) and it looked there was a shot of Rainbow Sun Francks (Lt. Aiden Ford), who I think was gone from SGA when Jewel took on the role of Dr. Jennifer Keller but would have been still playing Ford when Jewel was the female Wraith Ellia early in the show's run. So at least three other Stargate Atlantis cast members are involved in some capacity.

The One True b!X and Dean: I dunno...I didn't find the trailer LOL-level bad, though I can't say it's the best thing since sliced bread either. I personally would want to see the entire thing to know how good or poor it is, since I initially dismissed Sanctuary before growing to like it because of the heavy but imperfect use of nearly 100% green screens until enough production money got floated to allow for a mix of green screen and location/practical sets shooting.

Huh. I haven't seen SGA, and Staite, Hewlett, and Jason Momoa are the only cast members I know. Really interesting there are so many of them. Or maybe not considering it's a really small project, and one calls on who one knows?

I'm not in the habit of writing things off based on the trailers anymore. But motion novels aren't my thing. (So maybe I should watch the trailer, just to discuss properly. I don't know.) I'm just a bit glad Staite is doing something, and she gives the impression of being fond of the project. But then maybe I'm just a positive person.

Huh, don't remember seeing Jason Momoa in the trailer, but all the more awesome! Does make me wonder if Paul "Carson Beckett" McGillion is gonna show up to since I'm pretty sure Jewel name drops him a ton in social media posts. Or is it David Hewlitt? Anyway, someone amongst the major players named so far are BFFs with McGillion and he's seemingly up for stuff like this based on other roles he's done, especially his stint in Sanctuary.

Oh. Nah. I meant Momoa is the only other SGA cast member I know. I have no idea if he's involved. (Though really, I wouldn't be surprised if he was for some reason.) But there's eight episodes and that's plenty of time for some of these people to show up.